# 请补充若干行代码，完成向量积运算
ls = [111, 222, 333, 444, 555, 666, 777, 888, 999]
lt = [999, 777, 555, 333, 111, 888, 666, 444, 222]
s = 0
for i in range(len(ls)):
    s += ls[i] * lt[i]
print(s)
